Cell surface structure as a taxonomic character in the Thecamoebidae (Protozoa: Gymnamoebia)

Amoebae of the genera Thecamoeba, Platyamoeba , and Vannella , Family Thecamoebidae, have a surface layer which in one or more species of each genus has been found cytochemically to be a glycocalyx or mucoid coating. In six species of Thecamoeba , this is a compact coat, sometimes with a less dense outer region, 16–73 nm thick according to species. 7". proteoides , in other respects intermediate between Thecamoeba and Amoeba , has a filamentous layer up to 78 nm thick, somewhat like those of Amoeba and Chaos. T. granifera has a coating or tegument more than 0.5 Jim thick, differing structurally and cytochemically from the glycocalyces of the other species, and is the type-species of a new genus Dermamoeba. All six species of Platyamoeba investigated, freshwater and marine, had similar glycocalyces, consisting of a thin, dense inner layer and a thicker, lighter, outer layer. Two species of Vannella from North America bear complex structures here called glycostyles, corresponding in structure and size to those of V. simplex from Germany. There is an essential similarity between most species of Thecamoeba and the related Sappinia. Surface structure distinguishes clearly between Platyamoeba and Vannella but does not support fragmentation of the genus Platyamoeba. Although surface structure is of considerable taxonomic value at the generic level in the Thecamoebidae and may assist in confirming identification of some Thecamoeba species, it is less promising for differentiation of species within Platyamoeba and Vannella.     

A new genus of cave‐dwelling microcrustaceans from the Dinaric Region (south‐east Europe): adaptations of true stygobitic Cladocera (Crustacea: Branchiopoda)

We revise ‘true’ stygobitic cladocerans and lift three species from Alona Baird, 1843 (Cladocera: Chydoridae). Species of Brancelia gen. nov. are inhabitants of saturated karst, collected in pools of residual water in the amphibious zones of a few caves in the Dinaric Region, Europe. All species are blind (regression of eye and ocellus), have elongated sensorial equipment (aesthetascs) and a short rostrum, reduced antennal spines, and a globular body. In contrast to earlier hypotheses, there is no epigean chydorid taxon from the Palaearctic that can be linked to Brancelia gen. nov. The new genus may be an offshoot of six‐limbed Aloninae, but a littoral‐benthic ancestor is not apparent and most likely extinct. Evolution of Brancelia gen. nov. parallels that of other subterranean Cladocera like Phreatalona Van Damme, Brancelj & Dumont, 2009. We discuss the functional morphology of Brancelia gen. nov. and compare its adaptations to a subterranean life mode with those of Phreatalona. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 161 , 31–52.     

Pseudocitrobacter gen. nov., a novel genus of the Enterobacteriaceae with two new species Pseudocitrobacter faecalis sp. nov., and Pseudocitrobacter anthropi sp. nov,isolated from fecal samples from hospitalized patients in Pakistan

Four isolates of Gram-negative facultatively anaerobic bacteria, three of them producing NDM-1 carbapenemase, were isolated from hospitalized patients and outpatients attending two military hospitals in Rawalpindi, Pakistan, and studied for their taxonomic position. Initially the strains were phenotypically identified as Citrobacter species. Comparative analysis of 16S rRNA gene sequences then showed that the four strains shared >97%, but in no case >98.3%, 16S rRNA gene sequence similarities to members of the genera Citrobacter, Kluyvera, Pantoea, Enterobacter and Raoultella, but always formed a separate cluster in respective phylogenetic trees. Based on multilocus sequence analysis (MLSA) including partial recN, rpoA, thdF and rpoB gene sequence and respective amino acid sequence analysis it turned out that the strains also here always formed separate clusters. Based on further comparative analyses including DNA–DNA hybridizations, genomic fingerprint analysis using rep- and RAPD-PCRs and physiological tests, it is proposed to classify these four strains into the novel genus Pseudocitrobacter gen. nov. with a new species Pseudocitrobacter faecalis sp. nov. with strain 25 CIT^T (= CCM 8479^T = LMG 27751^T) and Pseudocitrobacter anthropi sp. nov. with strain C138^T (= CCM 8478^T = LMG 27750^T), as the type strains, respectively.     

A tyrannosauroid dinosaur from the Upper Jurassic of Portugal

Fragmentary theropod remains from the Upper Jurassic (Kimmeridgian) of Guimarota, Portugal, represent a new taxon of theropod dinosaurs, Aviatyrannis jurassica gen. et sp. nov. Together with Stokesosaurus from the Morrison Formation of North America, Aviatyrannis represents the oldest known tyrannosauroid, indicating that tyrannosauroid origins may be found in the Middle–Late Jurassic of Europe/North America. Furthermore, current evidence suggests that early tyrannosaurs were rather small animals, which is in general accordance with their origin amongst the generally rather small coelurosaurs.     

A small,narrow-beaked albatross from the Pliocene of New Zealand demonstrates a higher past diversity in the feeding ecology of the Diomedeidae

We describe a nearly complete, three-dimensionally preserved skull of a new albatross species from the late Pliocene (3.0–3.4 million years ago) Tangahoe Formation of New Zealand. Aldiomedes angustirostris, n. gen. et sp. has only about 90% of the length of the skull of the smallest extant albatross and is the geologically youngest record of a small-sized albatross known to date. The new species is characterized by a mediolaterally compressed beak, which is not found in any living albatross. The small size and some cranial features of A. angustirostris indicate that, in spite of its comparatively young geological age, the new species was not part of crown group Diomedeidae. We hypothesize that A. angustirostris was more piscivorous than extant albatrosses, which predominantly feed on squid. The reasons for the extinction of smaller-sized albatrosses are elusive but may be related to changes in seabird fauna during the Pliocene epoch, which witnessed the radiation of various non-procellariiform seabird groups.